This invention relates to a power system and, more particularly, to a power system which achieves a maximum operating efficiency by independent manipulation of the power plant r.p.m. and flywheel input and output r.p.m. all in recognition of predetermined power requirements.
Various power systems have been proposed in an attempt to efficiently move vehicles with an accompanying reduction of fuel consumption and/or pollutant emission. One system known as a variomatic transmission utilized expanding pulleys directly geared to the rear wheels. However, such a system was admittedly inefficient in supplying suitable torque to drive large vehicles. Moreover, past power systems utilizing manual or automatic transmissions are inefficient. In conventional systems, much of the horsepower supplied by the engine is lost during its delivery from the engine to the drive wheels. The resistance of the drive wheels, as transferred to the power train, presents various junctions of mechanical disadvantage which are overcome by increasing the horsepower of the power plant.
Also, the power plant in a manual transmission equipped vehicle is not under a flywheel load when the clutch disc is disengaged from the flywheel. When first gear is selected the power plant is brought up to a sufficient r.p.m. to engage the clutch disc with the flywheel at a sufficient torque to put the vehicle in motion. Thus, the acceleration begins. The power plant must increase its r.p.m. to increase the vehicle speed. The point at which the engine operates most efficiently is reached when the engine r.p.m. and torque peak curves coincide. Ideally at this point the shift to the next higher gear is made.
As the clutch disc is disengaged from the flywheel to shift to second gear engine r.p.m. drops. At this point inefficiency occurs as the power plant r.p.m. drops during the gear change. Thus, the flywheels kinetic energy, inducing the vehicle""s forward inertia, is lost. Thus, the conventional flywheel becomes a disadvantageous and unnecessary load on the power plant. Once the higher gear is engaged and the clutch disc re-engages the flywheel, the power plant must again produce the power necessary to propel both the flywheel and vehicle simultaneously, relying on the force produced by the combustion of the fuel/air mixture in the engine cylinders. Thus, piston/cylinder size is of importance.
This sequence of events is repeated with each gear change, road inclination (grade) change and vehicle acceleration.
Vehicles equipped with automatic transmissions never gain the advantage of increasing kinetic energy because of principles in hydraulics as applied to modern passenger vehicles. Although the constant drag on the power plant under idle conditions can be alleviated, the torque converter is a constant load on the power plant under all vehicle operating conditions. By the very nature of the automatic transmission equipped vehicle, the power plant and torque converter r.p.m. are always the same and the acceleration process begins at the low r.p.m. range of the power plant. No kinetic energy/inertia advantage is ever enjoyed. Thus, no advantage as to kinetic energy is ever ideally achieved in past vehicle power systems.
In response thereto I have invented a vehicle power system which utilizes an efficient power source preselected to move a vehicle at a range of preselected vehicle speeds with appropriate acceleration. The engine power is delivered to an input side of a flywheel at a precise r.p.m. by means of an intermediate, variable speed expansion pulley system as controlled by computer generated signals responsive to throttle depression and road grade. A second computer-controlled expansion pulley system is positioned intermediate the output side of the flywheel and transmission to deliver power to the downstream transmission. The control unit signals change the pitch of the expansion pulleys so as to efficiently and continuously transfer the power from the power source to the transmission without disengagement of the flywheel. In turn, the above problems are avoided as a plurality of ratios between the power plant and drive wheels are presented. Thus, small, high r.p.m. power plants can be utilized. The transmission is fluid controlled in coordination with selected vehicle speed ranges so that it will shift through efficient gears. Control of the input and output r.p.m.s, relative to the flywheel, enable one to pre-design an efficient power drive system. Also the accessories associated with the power system are driven at a constant functional r.p.m. Thus, no additional, unnecessary power need be delivered to power such accessories.
It is therefore a general object of this invention to provide a power system for a motor vehicle or the like.
Another object of this invention is to provide an efficient power plant which efficiently translates the energy of a power plant to the driven vehicle wheels.
A further object of this invention is to provide a system, as aforesaid, which provides a maximum safe power output for driving a selected vehicle load at preselected speeds.
A further object of this invention is to provide a system, as aforesaid, having an acceleration controlled by manipulation of the power plant r.p.m., flywheel r.p.m. and transmission so as to provide precise rates of acceleration and maximum top end speed.
Another object of this invention is to provide a system, as aforesaid, which provides an efficient rate of acceleration to the vehicle without the need to intermittently disengage the flywheel from the system.
Still a further object of the invention is to provide a system, as aforesaid, which allows for the preselection of an efficient power source so as to reduce the undesirable emissions emanating therefrom.
Another particular object of this invention is to provide a system, as aforesaid, which enables a preselection of efficient operating characteristics for a selected vehicle load.
A further particular object of this invention is to provide a system, as aforesaid, which provides for an efficient delivery of power for operating accessories associated with the system.
Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, a now preferred embodiment of this invention.